Conventionally, when reproducing, in parameter space, a three-dimensional shape model for use in CAD (Computer Aided Design) or CAM (Computer Aided Manufacturing) from the results of shape measurement of an object, a known technique is to create polygonal surfaces, such as triangles etc., by connecting each of a group of points with straight lines.
For example, Japanese Unexamined Patent Application, Publication No. 2003-346182 discloses a three-dimensional polygon data creating method which can obtain polygon data for an object surface with superior performance and stability from three-dimensional group-of-points data which are the results of shape measurement of an object, using a matching triangles method.    Patent Document 1:    Japanese Unexamined Patent Application, Publication No. 2003-346182 (pages 2 to 8, and FIGS. 1 and 4).